NHC-Catalyzed Ester Activation: Access to Sterically Congested Spirocyclic Oxindoles via Reaction of α-Aryl Esters and Unsaturated Imines
作者:Yonggui Chi、Lin Hao、Chan Chuen、Rakesh Ganguly
DOI:10.1055/s-0033-1338945
日期:——
asymmetric catalytic activation of esters should provide useful strategies for organic synthesis. Here we report a N-heterocyclic carbene (NHC)-mediated reaction of α-aryl acetic esters with oxindole-derived α,β-unsaturated imines. The reaction involves the formation of NHC-bound ester enolate intermediate from an ester as a key step, and furnishes spirocyclic oxindole products. The sterically congested
羧酸酯可以很容易地以低成本获得。因此,酯的不对称催化活化应该为有机合成提供有用的策略。在这里,我们报告了 N-杂环卡宾 (NHC) 介导的 α-芳基乙酸酯与羟吲哚衍生的 α,β-不饱和亚胺的反应。该反应涉及从酯形成与 NHC 结合的酯烯醇化物中间体作为关键步骤,并提供螺环羟吲哚产物。空间拥挤的螺环羟吲哚带有新形成的六元 δ-内酰胺,不能用其他方法轻松制备。